DALLAS -- Combining a "super aspirin" with bursts of a clot-busting drug during an angioplasty for patients experiencing a heart attack could offer the best strategy to quickly and safely open clogged arteries, Duke University researchers said at the annual American Heart Association scientific sessions.
Results of a dose-ranging trial show that using abciximab and two low-dose boluses of reteplase 30 minutes apart provided complete blood flow to up to 35 percent more patients than using abciximab alone or abciximab and a single dose of reteplase.
If the findings are confirmed and expanded in a larger clinical trial, pairing the drugs with angioplasty may offer a new standard of care for heart attacks, said the trial leader, Dr. Magnus Ohman, a cardiologist at the Duke Clinical Research Institute.
"Most patients now receive either a clot-busting drug or angioplasty to treat their heart attacks. Combining both together, and adding a second 'super-aspirin' drug appears to offer a very high success rate and may represent an exciting new step in treating most heart attacks," Ohman said.
He added that previous studies have shown that using a clot-busting drug alone is significantly less effective in restoring full blood flow (46 percent of patients), compared with using the right dose of a clot-buster and a "super aspirin" (63 percent of patients in this study had full blood flow after an hour).
Abciximab, known under the trade name Reopro, has been dubbed the ultimate aspirin because it stops blood from clotting, and reteplase, known as r-PA, dissolves blood clots. Both drugs are federally approved and on the market.
The Phase II dose-ranging trial, known as SPEED (Strategies for Patency Enhancement in the Emergency Department) was undertaken to find the fastest and safest way to open clogged arteries in a patient experiencing a heart attack. It was conducted in 61 hospitals with 305 patients from the U.S., Germany, Italy, Spain and Australia. SPEED was funded by Centocor and Eli Lilly, manufacturers of abciximab and reteplase.
SPEED is the first trial to test the use of both drugs with angioplasty, a procedure that presses plaque obstructions against an artery wall by inflating a small balloon from a catheter. Of the 305 patients tested, up to 80 percent had angioplasties, and of this group, another 80 percent received a stent.
It was also unique in that it enrolled patients within 60 minutes of being seen in an emergency department, instead of the standard 90 minutes, Ohman said. "That's because 60 minutes is within the time span most patients are sent for a primary angioplasty."
Patients considered for the trial were those suffering uncomplicated heart attack, and whose symptoms lasted less than six hours. Those patients who had a prior history of stroke, bleeding, and heart surgery, among other factors, were not included.
Using abciximab (a bolus 0.25 mg/kg; infusion 0.125 micrograms/kg/min) alone or with reteplase, the researchers found that after 60 minutes:
63 percent of patients given abciximab with two low-dose (5 unit) boluses of reteplase 30 minutes apart had full blood flow.
One low dose (5U) bolus of reteplase with abciximab gave 53 percent of patients restored blood flow.
Adding r-PA to the regimen resulted in no increased bleeding.
Only 28 percent of patients given abciximab alone had restored blood flow.
Because the study is limited and does not yet include such clinical endpoints as death and a second heart attack, Ohman cautioned that a larger clinical trial should be undertaken to expand the trial. "We can open more vessels if we use this combination, but it begs the question of whether it will eventually improve outcomes, and that needs to be tested in larger trials," he said.
Note to editors: Results of the SPEED trial will be discussed in an AHA news conference at the embargo time and date listed above, in Room A215-A217 at the Dallas Convention Center.